It is generally known that electronic systems are provided for automatically gathering data concerning television viewing habits for such purposes as program ratings, market research and the like. Such systems, some of which are referred to as "tuning people meters", typically include a capability for determining a source, such as a broadcast channel, of the programming reproduced by the television set, as well as the composition of the audience.
As market requirements for such monitoring devices have developed, the gathering of more data, and more complex data, concerning television viewing has been demanded, and it has also been found to be desirable to make the monitoring devices as easy to use, and as transparent to the viewer, as possible. These developments, and the resulting evolution of monitoring equipment, has caused such equipment to become increasingly complex and somewhat expensive.
At the same time, the average number of television sets per household has in general increased. In order to assure accurate data gathering with respect to the viewing habits of members of a household, it has usually been the practice to install a monitor in association with each television set in the household. However, it is believed that in a significant number of households in which monitoring equipment is installed, one or more of the television sets therein are seldom if ever used. In such cases, it would be desirable to avoid installation of a monitor with respect to the little used television set or sets without compromising the accuracy of the television viewing data that is to be gathered for that household.